Electric contact device.



T. H. McQUOWN. ELECTRIC CONTACT DEVICE. APPLIOATION FILED mum, 1909.

Patented Feb. 1'7, 1914.

WITNESSES Illlllll UNITED s'rATEs PATENT OFFICE.

rHoMAs n. moouown, or CAMBRIDGE, MASSACHUSETTS,- Assmnon 'ro An mus.

ATWATER KENT, or PHILADELPHIA, PENNSYLVANIA.

EL'Ec'riuc Conner n'nvren.

To all whom it may concern:

the followingis a full, clear, and exact disclosure.

My invention relates to electric contact devices, but especially to that kind of device in which it is desirable to obtain a certain positive and rapid make and breakof an electric. circuit, such, for example, as to make it especially applicable for those operating the sparking circuit of an internal combustion engine, my invention being particularly adapted for use in connection with the sparking circuit of the engine of an automobile, although my invention is not to'be construed as being limited to such use, inasmuch as it is'adapted to open and close any electr c circuit in which the requirements as above set forth are necessary or desirable.

The object of my invention is to provide an electric contact device in which the time of the closure of the circuit is constant, irrespective of the speed of the mechanism to which it is attached, or by which it is operate to provide a device in \which the time of closure is substantially instantaneous whether the operating mechanism is moved at a slow or rapid rate of speed; to make It impossible for the machine or operating mechanism to stop in such a positionas to,

leave or hold the circuit closed and waste the ;current; to prevent the accidental closureof the circuit; to operate the circuit.

closer by a rotary member attached directly to a rotating shaft, adapted to be directly. coupled with the drive shaft' of an internal combustion engine; to provide a means whereby the circuit will notbe closed when the driving shaft is rotated in the'reverse direction; to provide a device which 1s comaratively cheap, simple and not liabl to Become disarranged -or require constant at- 'tention.

Other objects of my invention appear in the s ecification and-claims below. Re erring now to-th-e drawings formin a part ofthis specificatiom-and in whic the same reference characters are employed to designate thesamenumbers throughout .is plainly shown in the various views; Fi ure 1 is a top plan yiew ofmy improved contact device Fig. 2 s a similar view showing some of the parts in cross-section; Fig. 3 is a side elevational View of my. device showing diagrammati- Cally the electric connections, and Fig. 4 is {a perspective view of a detail of construc- Within a suitable mountin or housing 1 is mounted a shaft 2, adapte to be rotated from any suitable source of motion. This is a shaft to which the main shaft of an internal combustion engine may be attached when the device is to be usedin con ction withthe sparking circuit of such an ngine. This shaft 2 is j ournaled in a plate 3 which forms the base or su port of my contact de-. vice. The outer en of the shaft 2 is pro vided with a cage orcarrier 4; consisting of two side plates 55, spaced apart from each other and rigidly held together by suitable belts or pins 6, the whole cage or carrier 4 being loosely mounted, that is to say normally free to be rotated, upon the shaft 2. The extreme outer end of the shaft 2 is providedwith a ratchet 7, made fast thereto in any suitable manner, as-b-y providing the said end of the shaft with a flat surface, and fitting the said flattened end into a suitable openin Tigs. -1 and 2. The ratchet may be prevented from slipping 01f the end of the shaft by means of a pin 8, arranged outside of the ratchet and passing through the end of the shaft, or by any other suitable means.

To the side of the outer plate 5 is pivoted a pawl 9, adapted to cooperate with the in the said ratchet,

ratchet so that when the shaft'2 is rotated in the direction of the arrow shown in F1gs. 1 and 2, the pawl 9 will engage the cage in the ratchet 7, and rotate the carrier in the same direction. When, however, the

shaft 2 is rotated in the opposite direction, the pawl 9 willride over the face of the ratchet without moving the cage or carrier 1. Within the cage 4 I arrange a series of small shafts l0v substantially equidistant from theax'is of the shaft 2, and upon each of these shafts 10 I mount a pair of outwardly extending members 11-11, spaced apart from 'each other, the outer ends cf said arms 11 carrying a small roller 12 adapted to loosely turn upon a bearing pin or. journal 13. These members 11-11 which form anoutwardly extending arm are normallyfirmly but yieldingly pressed against the bearings or pins 6, forming a part of the cage 4, by a coil spring 14, one

. end of which is preferably wrapped around the pin 6 and the other end, after being wrapped around the shaft 10, is secured'to one o the members 11. From this arrangement it will be apparent that each of the rollers 12 is supported upon an outwardly extended arm, pivoted upon the shaft 10 and normally firmly pressed against the adjacent shaft or pin 6.

Adjacent one side of the cage 4 I arrange a depressing member or plate 15, the inside side of which is curved eccentrically to the axis shaft 2, and so arranged with respect thereto that when the cage tis rotated the rollers 12 first pass under the depressing member 15, but as they continue to be carried along by the rotation of the cage the rollers will press against the said depressing member 15 and the arms 11 will be depressed or forced rearwardly away from their stop" pins 6, against which they normally rest, as plainly illustrated in Fig. 1.

Above the depressing member 15, I pro, vide the movable member 16 of the make and break device, the same consisting of a latch 16, pivoted on a stud or shaft 19, having one end 16 depending into the path of the roll ers 12. The said latch is yieldingly held binding post 26.

against a suitable stop (which in this case is shown as the end of the depressing member 15) by means of a spring 17 one end of which may be attached to a pin-18 upon the plate 3, and the other end of which, after being wrapped around the pivot pin or stud 19 of the said latch, is fastened to the upper side of the latch to hold it against the plate 15, as plainly shown in Fig. 3. The latch,

. 16 is further provided with a contact point 20 which may be mounted upon the outer end of a coil spring 21 Wrapped around the pivot pin or stud 19, theother end of said spring 21 being secured tosaid latch in any suitable manner. That end of said spring 21, which carries the contact point 20, is normallyheld pressed against the stop pin 22 also carried by said latch 16.

Adjacent contact .point 20 is mounted a relatively stationary contact point 23, adjustable however so as to vary the distance between the contact points '20 and 23. Iv have shown the relatively stationary contact point 23- as a screw threaded through a block 24, mounted upon an insulated bushing 25, by which the stationary contact point is insulated from the plate 3. The block 24 has a stem passing through said insulating block 25, and said stem is provided with a suitable In the operation of device the electric circuit is completed through the binding post 26, lead 27, battery 28, and primary the rollers 12 pass beneath the pressing plate or member'15 they are depressed or forced away from their respective stop pins 6 and their speed is retarded. When, however,

each roller passes beyond the end of the de' pressingplate 15, the tension of the springv 14 quickly returns the levers or arms 11 back against their stop pin 6, but in doing this the roller 12 will impinge upon or strikethe depending end 16 of the latch 16 and turn the latch 16 upon its pivot 19 as indicated in dotted lines in Fig. 2. This movement of the latch- 16 brings the contact points 20 and 23 into engagement and effects a closure of the circuit. It is to be noted, however, that the arms 11 havebeenso far depressed or retracted by the depressing plate or member 15 that, when released, they will snap to a position back against their stop pin 6 which at that time is beyond the path of movement of the said end 16 and consequently the roller will not prevent or interfere in any way with the immediate return of the latch to' its normal position under the influence of the spring 17, thus substantially instantaneously effecting a break in the circuit. From this it will be seen that should the machine stop immediately after a roller has been released from the depressing member 15, the roller would first strike the end 16 of the latch 16 and move the latch to close the circuit, and that the roller would then move beyond the path of said end 16 so that the circuit would be immediately broken. By mounting the contact point 20 upon the end of the spring which normally rests against pin 22, the stationary cbntact pin or screw 23 can be so adjusted that the contact points 20 -and 23 will be normally out of actual engagement but very close to each other. When, therefore, the latch is turned upon its pivot pin 19 and the contact points are brought in engagement, the spring 21, carrying the contact point 20 will'be forced away from the pin on stop 22. This allows the contact points to be held yieldingly together for a very short length of time, but fora sufficient time to insure a certain closure of the circuit. When the shaft 2 is rotated in the reverse direction, roller 12 will bring up against the outer side of the depending end.

16 of the latch 16, without turning the said latch upon its pivot pin 19 andthis prevents any'further reverse movement of the cage or carrier 4, permitting the pawl 9 toride over the ratchet 6.

Although I have described one form of device embodying my invention, I do not wish to be construed as limiting myself to the exact structure as above set forth, since my invention may be constructed and oper- 1. In a'contact device the combination of a rotatable shaft, a carrier loosely mounted thereon, a pawl and ratchet connection between said carrier and said shaft, an arm extending outwardly from said carrier, a stop on said carrier, means to normally hold said arm yieldingly against said stop, means extending into the path of movement of said arm to depress said arm and' to force it away from said stop, and to then release said arm and allow the same to return substantially instantaneously to its position against said stop, a support stationary with respect to said carrier, and a contact point carryingmember, mounted on said support, and operatively engaged by said arm upon the release of said arm from said depressing means. 0

2. In a contact device the combination of a rotatable carrier, an arm carried thereby, means engaged by said arm to retard the movement of said arm during a portion of its travel, and to then release said arm, tension means between said carrier and said arm to'advance said arm upon its said release, a support stationary with respect to said carrier, and a contact point member mounted on said support and situated in the path of said arm immediately beyond the point of the release of said arm.

3. In a contact device the combination ofmeans for closing the contact points comprising a carrier, a shaft on which said carrier is mounted, an arm projecting from said carrier, a stop against which said arm is yieldingly pressed, anti-friction means mounted in the ends of said arm and an ec- 1 thereby, an eccentric cam surface cooperating with said arm during a portion of its travel to retard the movement of said arm, said arm returning to its normal position as soon as the operative enga ement of said arm and cam ceases, a stationary contact point, a movable contact point, and a movable member upon which said movable contact point is mounted, said member being operated by said arm, upon its release from said cam surface to bringsaid contact points into momentary engagement.

5. In a contact device the combination of a. shaft, a yielding arm driven thereby, means to rotate said shaft, an are shaped cam surface arranged eccentrically to the path of the end of said arm and extending 1nto the path of said arm, to comparatively gradually retard the forward movement of I said arm during an arc of its movement, and to then release said arm and allow the same to rapidly return to its normal position, said cam forming a stop for preventing the rotation of said arm in a reverse direction, and a pawl and ratchet driving connection between said shaft and said arm.

6. In a contact device the combination of a rotating carrier, an arm projecting therefrom and carried thereby, means extending into the path of the rotation of said arm for retarding the rotative movement of said arm during a portion of its travel, means to restore said arm to its normal position immediately after it passes out of engagement with said means projecting into its path, and a circuit closing member stationary with respect to said carrier momentarily engaged by said arm immediately after the release of said arm from said means projecting into its path to open and close a circuit.

7. In a contact device the combination of a shaft, a rotating carrier mounted thereon, an arm carried by said carrier, means to hold a said arm in a normal position, means engaged by said arm during a portion of its travel around the axis of said shaft to retard the rotative movement of said arm, said means to hold said arm in normal position being operative immediately after said arm passes from engagement with said means for retarding its motion, and a circuit closing member stationary with respect to said carrier operated by said arm immediately after said passes from its engagement with said means for retarding same, to momentarily close and open a circuit.

" In witness whereof, I have hereunto set my hand this 31st day of December 1908.

THOMAS H. McQUOWN.

Witnesses: I I

LOUIS C. SMITH, BERTHA F. Hnnsnn. 

